One of the most salient putative African features of Palenquero, an Afro-Hispanic creole spoken in northern Colombia, is the prenominal plural marker ma. However, plural number is not categorically marked with ma, which alternates with bare forms in plural contexts and also occurs in singular contexts. In a principled sample of noun phrases (n = 1,186) from the spontaneous speech of twenty-seven Palenquero-Spanish bilinguals, the rate of ma (versus zero) is 51% in plural and 13% in singular contexts. Singular ma is favored with subjects and specific objects, consistent with an association with definiteness. In plural contexts, where it is robust, selection of ma is favored with specific and generic referents in subject role. This conditioning indicates that plural marking is favored for discourse referential nouns, in accordance with the cross-linguistic generalization that morphological marking tends to appear on instances that approach the prototypical function of a category (Hopper & Thompson, 1984).